Surface treating apparatus



Sept. 27, 1949. H. BISHOP EIAL summon TREATING APPARATUS 2 Sheets-Sheet 1 Filed May 24, 1948 INVENTORS LEW/S H. B/sHop J SrA/VLEY F/NN Sept. 27, 1949. H; BISHOP ETAL SURFACE TREATING APPARATUS 2 Sheets-Sheet 2 Filed May 24, 1948 ama Patented Sept. 27, 1949 SURFACE TREATING APPARATUS Lewis H. Bishop and John Stanley Finn, Burlingame, Calii'., assignors, ments, to William H. Mead,

by mcsne assign-W Oakland, Calif.

Application May 24, 1948, Serial No. 28,858

8 Claims. (01. 51-8) This invention relates to surface-treating apparatus. In particular it relates to improvements in the operating head of an abrader in which the abrasive material is impelled against a working area by a strong pressure blast and is then removed from the working area along with the abraded particles by an even stronger suctioncurrent, for collection in a receptacle.

This invention is particularly well suited to solve the problem of cleaning machinery having uneven or relatively intricate surfaces, such as tire molds and the like. Ordinary abrasive cleaning devices widely scatter the grit and abraded particles in the vicinity of the object being cleaned. This is not only a hazard, but considerable time must be spent in cleaning up the debris once the abrasive operation is complete. An alternative abrading method is to place the piece being cleaned within a blast cabinet, but this technique is obviously of limited application and is somewhat impractical at best.

The problem has been how to provide a mobile abrader which could be brought to the machinery or other object to be cleaned and there clean it in place, but with the simultaneous collection of all the abrasive particles and debris. This problem was solved in a general way by the apparatus described in the patent to William H. Mead, No.

2,455,514, issued December 7, 1948 and in the copending applications, Serial No. 55,243, filed October 18, 1948, and Serial No. 778,378, filed October 7, 1947. However, the operating head (sometimes described as a gun) of the unit described in said applications, is not particularly well adapted for use with uneven, or non-planar surfaces such as those present on tire molds, for example. Further, in the unit described in said applications, the mounting of the blast and suction lines leading to the operating head is entirely separate, and for that reason manipulation of the head is made relatively cumbersome; it would be more convenient if a single connection could be used in the immediate vicinity of the head.

It is therefore an object of this invention to provide an improved operating head for use with an abrader of the type which simultaneously blastimpels and suction-removes the abrasive with impinging air currents drawn in through the air pervious skirt.

Another object of this invention is to provide an operating head of the foregoing variety which can be used in treating uneven, curved, or irregularv surfaces, particularly those having small crevices, as the interior of tire molds.

Another object is to provide an operating head of the type indicated which can be used in'treating intersecting surfaces, as corners and the like.

Another object of this invention is to provide a light-weight cleaning unit having only one abrasive-conducting line leading into the blast-directing gun or head held by the operator, whereby manipulation of thegun is rendered extremely simple and akin to employing a whisk-broom.

A further object of this invention is to provide an operating head which can be adjusted to vary the area and intensity of abrasive impingement, the adjustment also compensating for wear of parts and for difierent types of surface-treating materials which may be employed.

Other objects and advantages of this invention will appear in the course of the following description given in accordance with U. S. Revised Statutes, Sec. 4888, though without intending to limit the scope of the invention'otherwise than as claimed.

In the drawings:

Fig. 1 is a view in elevation and in section of an operating head which embodies the principles of this invention; for purposes of clarity the bristles in the rear are omitted, although they encircle the head as shown in Fig. 2;

Fig. 2 is a reduced bottom plan view, looking up into the open mouth of the head shown in Fig. 1;

Fig. 3 is a view in elevation, somewhat schematic in nature, showing a surface-treating apparatus of the type withwhich the operating head of Fig. 1 may be used; I

' Fig. 4 is a view in front elevation of a modified form of operating head which is particularly well suited for cleaning the area in and around the intersection of two surfaces; the bristles in the rear are omitted for clarity of illustration, although they enclrcle the head as shown in Fig. 5; and

Fig. 5 is a reduced view looking into the open end of the head shown in Fig. 4; the dark vertical line represents the edge where the brush segments converge.

A brief description of the surface-treating apparatus illustrated in Fig. 3 will be helpful in understanding the principles of the improved operating head which is generally shown at [0 therein. An air compressor l I furnishes a stream of highly compressed air to the duct l2. In a manner fully described in the aforesaid Patent No. 2,455,514, the abrasive is fed into this airstream from a hopper 13 through a valve M, a-

conduit l5 then carrying this abrasive-filled airstream to the operating head It where the abrasive particles impinge on the surface l6 to be cleaned. A powerful suction pump 20 is also connected to the operating head ID by a series of conduits through which the spent abrasive and any waste particles dislodged thereby are drawn back into the unit and are prevented from passing outwardly of the head l into the atmosphere. Specifically, the waste and spent abrasive are carried away from the head through a conduit 2| to a reclaimer 22 (described in the co-pending application, Serial No. 778,378) where any reusable abrasive material is separated from the waste and passed into an upper hopper 23 from which it is periodically discharged into the main feed hopper IS. The waste is sucked out from the reclaimer 22 through a conduit 24 into a dustcoliecting bin 25.

Generally, this present invention comprises an operating head It) which serves to direct against a surface Is to be cleaned the abrasive or .other treating material supplied by the unit described, and which thereafter facilitates the withdrawal of the abrasive and waste particles from the surface Hi and back into the unit before they can escape to the surrounding areas and into the atmosphere.

The head In will now be described in detail (see Fig. 1). It comprises an elbowed housing 30 open at both ends, the lower end 3| facing but spaced above the work surface I6 to be cleaned and the upper end 32 being detachably connected with the suction duct 2|, here shown as fabricated of rubber. Secured within the housing 30 adjacent the outer corner of its elbow is a fitting 33 having an angular bore 34 therein, the fitting being internally threaded adjacent the respective ends 35 and 36 of the bore. The end 35 of the bore is aligned with the upper end 32 of the housing 39 and serves to threadably engage the lower end of a rigid blast-conducting tube 31 connected at its opposite end to the fiexible blast conduit l5. As indicated in Fig. 3, the conduit I is received within the suction duct 2| as those members approach the head It. This arrangement makes for a greatly improved convenience of operation as regards manipulation of the head, for there is only one apparent conduit leading directly into the head.

Threaded within the end 36 of the fitting 3| is a nozzle 38 having a threaded neck portion 39 provided with an annular flange 48 for engagement with the fitting 33. The nozzle also has a relatively narrow bore 4| communicating with a flared orifice 42 .of inverted cone shape which terminates adjacent the lower end 3| of the housing. The upper end of bore 4| is also slightly flared at 43 for better communication with the bore 34 of fitting 33 and with the tube 31. The mounting of nozzle 38, fitting 33, and tube 31 within the housing 30, is such as to leave an unimpeded passageway for withdrawal of the waste particles back through the housing and into the suction duct 2|.

Slidably mounted without the lower end of the housing 30 is a collar 50 from which depend a series of brush-retaining projections 5|. Set within these projections, and bound by wires 52, are the upper ends of both an inner series 53 and an outer series 54 of brush bristle elements. The collar 50 is downwardly and outwardly flared at 55, and its outer edge is upturned at 56 to provide a vertical margin. The collar 50 also carries an upper flange 51 having a set screw 58, tightening of this screw serving to fix the collar at any desired position with respect to the housing 30.

Slidably mounted about the upturned edge 56 of collar 50 is a skirt member 60 which in effect 4 constitutes an adjustable and vertical extension of the collar and is held in place by the screw 6|.

Turning now to the brushes 53 and 54 which depend from the collar 50, it will be observed that they form concentric rings around the opening 30, the outer brush ring 54 being made up of long and relatively flexible elements, as pig or nylon bristles. The elements of the inner brush ring 53 are preferably somewhat shorter and stiffer than those in the outer ring, and are normally made of wire. This inner brush ring 53 has a dual function; first, as a still, spacing member which tends to support the head In at the desired distance from the work surface It; and, second, as a maze-like impeding means which more or less serves to confine the expelled abrasive particles, while at the same time admitting air from the atmosphere outside the head.

The purpose of the outer brush ring 54 is to provide an auxiliary abrasive restraining or containing ring. The bristles in the outer ring 54 are somewhat longer and are more flexible than those in ring 53, so they conform readily to irregularities of surfaces, such as the pattern of a tire mold, and thereby prevent leakage of the spent abrasive and the waste while still permitting the all-important inward passage of the air current, induced by the suction line 2|.

The adjustment feature of the collar 50, as determined by the setting of the screw 58, enables the nozzle 38 to be pre-set at any desired distance from the work surface "5 in order to get the best results for each type of abrasive and surface. The skirt 6B permits of a still further control of the cleaning operation, for by raising or lowering the skirt with relation to the collar 50, the force or intensity of the incoming air current is readily controlled. For example, by adjusting the skirt 60 so that it is only about inch above the surface It when the head I0 is in place, a very intense impingement of currents is obtained in the working area adjacent the bristles 53. A wider gap will slow down the entering air current. Both these adjusting means enable the operator to compensate for wear of the bristles 52 and 54.

The modified form of gun I0 illustrated in Fig. 3 is in all respects like the gun illustrated in Fig, 2 except that the elements of its inner and outer brush rings H and 12 are so set within the adjustable collar 73 as to be disposed in a generally angular direction with respect to the outer wall of housing 14. Further, the adjustable skirt 15 is outwardly flared at its bottom portion I6 that the adjacent brush elements 12 may not be unduly confined as the skirt I5 is lowered. With this arhead comprising a hollow housing open at each end, the lower end being arranged to face the work surface and the upper end being adapted for conperiphery of said lower housing end, said impeding means comprising an inner ring oi relatively stiii brush elements and an outer ring of brush elements which are relatively longer and more flexible than are those of said inner ring.

2. The operating head claimed in claim 1 in which the maze-like impeding means is vertically adjustable with respect to the lower end of the housing.

3. The operating head claimed in claim 1 in which a continuous skirt depends about the outer periphery of the maze-like impeding means and terminates above the work-engaging end of said means.

4. The operating head claimed in claim 1 in which the inner ring of the maze-like impeding means comprises a wire brush and the outer ring thereof comprises a bristle brush, the bristles in said bristle brush being relatively longer and more flexible than are the wires in said wire brush.

5. The apparatus claimed in claim 1 in which the outer, work-engaging extremities of the brush elements in the respective inner and outer rings lie on two intersecting planes, whereby a corner work surface may be treated.

6. The operating head of claim 1 wherein the upper end of said conduit and an adjacent portion or its connected blast line are surrounded by the upper end of said housing and an adjacent portion of its connected suction line.

7. An operating head for a blast-impelling suction-removing, surface-treating apparatus, said head comprising a hollow housing open at each end, the lower end being arranged to face the work surface and the upper end being adapted for connection with a suction line; a conduit extending within said housing and mounted therewith to provide between said conduit and said housing a suction passageway connecting said lower and upper housing ends, the upper end of said conduit bein adapted for connection with a blast line and the lower end oi. said conduit terminating adjacent the surrounding lower end of said housing; a maze-like impeding means depending from the periphery of said lower housing end, said means being vertically adjustable with respect to said lower housing end and'comprising an inner ring of relatively stifl brush elements, and an outer ring of longer and relatively flexible brush elements; and a vertically adjustable skirt about the outer periphery of said maze-like impeding means,

8. The operating head claimed in claim 7 in which the inner ring of the maze-like impeding means comprises a continuous wire brush, and the outer ring comprises a continuous bristle brush, the bristles of which are relatively longer and more flexible than are the wires in said wire brush.

LEWIS H. BISHOP.

J. STANLEY FINN.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 467,155 Clarke Jan. 19, 1892 1,752,664 Forcier Apr. 1, 1930. 2,242,182 McCann May 13, 1941 2,343,875 Schwartz Mar. 14, 1944 2,455,514 Mead Dec. 7, 1948 FOREIGN PATENTS Number Country Date 108,256 Australia Aug. 11, 1939 

